Flexible tube connection

ABSTRACT

A tube connection wherein the tube end is provided with an enlargement for positively retaining the tube end in a fitting having a resilient annular seal member received between the enlargement and a flange of the nut member. The tube end enlargement may be secured to the tube end or may be formed in the tube end such as by a conventional first step of a double flare operation. The fitting flanged outer portion effectively limits the outward movement of the tube end by engagement of the enlargement therewith in the event that the tube end is drawn outwardly through the seal member.

United States Patent [72] Inventors Leonard J- Kowtll 2,458,817 1/1949Wolfram 285/354X Prospect Heights; 2,578,933 12/1951 Hunter et al285/52X Fritz A. Delander, Beverly Hills, Ill. 3,400,953 9/1968 Sullivan285/50 1 pp 7,3108 969 FOREIGN PATENTS :25: d 5: 250,541 3/1964Australia 285/234 Assignee Imperial corporation 472,773 9/1937 GreatBritain 285/234 Primary Examiner-Dave W. Arola Attorney-Hofgren, Wegner,Allen, Stellman and McCord [54] FLEXIBLE TUBE CONNECTION 15 Claims, 5Drawing Figs. [52] 11.8. C1. 285/233, ABSTRACT: A tube connectionwherein the tube end is pro- 235/354 vided with an enlargement forpositively retaining the tube [51] Int. Cl F16] 21/00 d i a fittinghaving a resilient annular seal member received [50] Field ot'Search285/233, b tw e the nlargement and a flange of the nut member. The 48,236 tube end enlargement may be secured to the tube end or may be formedin the tube end such as by a conventional first step [56] ReferencesCited of a double flare operation. The fitting flanged outer portionUNITED STATES PATENTS effectively limits the outward movement of thetube end by 2,212,745 8/1940 McIntosh 285/233 engagement of theenlargement therewith in the event that the 2,422,158 6/1947 V 1fram..285/233 tube end is drawn outwardly through the seal member.

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FLEXIBLE was CONNECTION BACKGROUND OF THE INVENTION 1. Field of theInvention This invention relates to tube fittings and in particular totube fittings having resilient means for supporting the tube endtherein.

2. Description of the Prior Art In conventional flexible tube fittings,the tube end is supported by a resilient seal member provided within thefitting. A serious problem arises in the conventional fittings, however,in that the tube end may be pulled outwardly through the seal member andfrom the fitting as a result of the relatively impositive retention ofthe tube end therein by the resilient support means. Anotherdisadvantage of the known flexible tube fittings is the inabilitythereof to maintain the sealing connection over a wide temperaturerange. Still further, the known flexible tube fittings have thedisadvantage of difficulty of maintaining the sealed connection up tothe burst pressure of the tubing. In certain of the flexible tubefittings, metal-toinetal contact between the tube and metal portions ofthe fitting limits the flexible connection characteristics thereof.Another disadvantage of certain flexible tube fittings is the difficultyof removing the sealing member for replacement thereof. Still further incertain of the flexible tube fittings, the resilient sealing member maybe improperly installed by virtue of an asymmetrical constructionthereof.

Another disadvantage of known flexible tube fittings is the difficultyof maintaining the tube end in the fitting against relatively highpressures as well as maintaining the seal under such high pressures. Afurther disadvantage of certain known flexible tube fittings is arestriction in the flow passage therethrough. Yet another disadvantageof the known flexible tube fittings is the failure to provide means forpositively preventing failure of the sealed connection under highpressures, severe temperature conditions, vibration, and high axialtension conditions.

Still another disadvantage of the known flexible tube fittings is therelative complexity and high cost thereof.

SUMMARY OF THE INVENTION The present invention eliminates theabove-discussed disadvantages of the known flexible tube fittings in anovel and simple manner. More specifically, the present inventioncomprehends an improved tube connection wherein the tube end iseffectively positively retained in sealed association with the fittingnotwithstanding relatively large forces tending to urge the tubeoutwardly from the fitting and under a wide range of temperatureconditions. Further, the present invention comprehends such a tubeconnection wherein the tube end is normally resiliently supported freeof metal-to-metal contact with the fitting while yet permitting angularadjustability of the position of the tube end relative to the fittingover a relatively wide range.

The invention further comprehends the provision of such a tubeconnection wherein the distal end of the tube defines a radialenlargement adapted to abut the resilient seal member of the fitting toprovide an improved positive retention of the tube end in the fitting.The invention comprehends the provision of the enlargement at the outerend of the tube by suitable means such as by securing an annular elementthereto as by compression, brazing, adhesive fastening, etc., as well asby forming the enlargement directly in the tube end itself. In theillustrated embodiment, the enlargement is formed in the tube and morespecifically, is provided by performing the first step of a double flareoperation on the tube end. The annular seal member may be installedprior or subsequent to the provision of the enlargement in the tube end,as desired.

The tube connection is adapted to maintain a sealed connection of thetube end with the fitting over a substantial temperature range and hasbeen found to be effective to retain the tube end in association withthe fitting up to and beyond the burst pressure of the tubing. Theresilient support of the tube end effected by the seal member dampensvibrations and resiliently supports the tube end to preventcrystallization of the tubing material as often occurs in theconventional tube fittings. The seal member is readily removable forfacilitated maintenance of the fitting. The seal member is symmetricaland, thus, cannot be installed in the fitting improperly.

The arrangement of the fitting is such that forces which tend to urgethe tubing outwardly from the fitting cause an increase in the pressurethereagainst by the sealing support member. Resultingly, the sealingpressure between the tube end and the seal member is proportional to thepressure of the fluid in the fitting. Thus, the tube connection of thepresent invention provides a positive seal of the tube end into thefitting at pressures up to and beyond the burst pressure of the tubing.

The fitting is further arranged to have a positive mechanical interlockwith the tube end in the event that the tube end is moved through theresilient seal member. Thus, blow out of the tube end from the fittingis effectively prevented. The fitting is arranged to provide anunrestricted flow passage through the tube connection. The fitting isextremely simple and economical of construction and provides longtroublefree life.

More specifically, the tube connection of the present inventioncomprehends a fitting having an internal space for receiving a tube end,an outer wall portion defining an opening through which the tube endextends into the space, a resilient annular seal member in the spaceadjacent the wall portion, with the tube end extending through themember to axially inwardly thereof, and an annular radially inwardlyopening enlargement in he distal end of the tube axially inwardly of theseal member. BRIEF DESCRIPTION OF THE DRAWING Other features andadvantages of the invention will be apparent from the followingdescription taken in connection with the accompanying drawings, wherein:

FIG. 1 is a fragmentary diametric section of a tube end, showing thestep of providing the annular enlargement in the distal end thereof;

FIG. 2 is a diametric section of a tube connection embodying theinvention, prior to makeup of the fitting;

FIG. 3 is a diametric section similar to that of FIG. 2, illustratingthe connection as upon completion of the makeup of the fitting;

FIG. 4 is a fragmentary diametric section illustrating the arrangementof the tube connection whereon the tube end has moved outwardly throughthe seal member to abut the nut flange; and

FIG. 5 is a fragmentary diametric section of a modified form of tubeenlargement means embodying the invention. DESCRIPTION OF THE PREFERREDEMBODIMENTS In the exemplary embodiment of the invention as disclosed inFIGS. 1-4 of the drawing, a tube connection generally designated 10 isshown to include a fitting generally designated 11 for connection to theend of a tube 12. The fitting may include a body member 13 and acooperating nut member 14 threadedly associated by means of threadedportion 15 on the body member 13 and threaded portion 16 on the nutmember 14. The nut member includes an axially outer inturned flange l7defining a wall provided with an axial opening 18 through which the tube12 extends. The-fitting ll defines an internal space 19 in which thetube end 12 is received. The fitting further includes an annular seal 20which, as shown in FIG. 2, is coaxially disposed about the tube end 12,axially inwardly of the nut flange 17. Seal 20 extends axially betweenthe flange 17 and a shoulder 21 on the body member.

As shown in FIG. 1, tube end 12 is provided with a distal portion 22defining a radially inwardly opening enlargement. The enlargement 22 maybe formed by a conventional die 23 cooperating with a suitable support24 to form in the distal end of the tube 12 a first flare of aconventional double flare. In such a first flare, the end portion 25 iseffectively turned radially inwardly to comprise a flat substantiallyplanar end portion, with the axially outer portion 26 of the flareextending generally frustoconically into a tubular connection 27 to thetube 12 as a result of the provision of a frustoconical backup surface28 in the support member 24. As shown in F IG. 1, the internal diameterof the end portion 25 is generally similar to the internal diameter ofthe tube 12, whereas the outside diameter of the portion 22 issubstantially larger than the external diameter of the tube 12.

Seal may have any suitable configuration, e.g., a split ring, a coil,etc., and in the illustrative embodiment as shown in FIG. 2, the seal 20comprises an annular, elastomeric member having an internal diametersubstantially equal to the external diameter of the tube 12 so as tohave a snug fit therewith in the assembled relationship. The diameter offlange opening 18 is made to be slightly greater than the externaldiameter of the tube 12, but substantially less than the outsidediameter of the enlargement 22 as best seen in FIG. 4 so as topositively preclude the axial withdrawal of the tube end from theassembled arrangement of the fitting as shown in FIG. 2.

The seal 20 is compressed between nut flange 17 and body surface 21, asshown in FIG. 3, to provide a positive sealed sole support of the tubeend outwardly of the enlargement 22 while permitting axial displacementof the tube end inwardly of said seal. As the enlargement extendsradially behind the seal 20, withdrawal of the tube axially outwardly iseffectively precluded. Fluid pressures acting to urge the tube end 12axially outwardly merely increase the reaction pressure of the seal soas to maintain a stable, positive, sealed support of the tube endagainst high pressure.

As enlargement 22 is externally rounded at 29, the seal 20 may bereadily removed by slightly stretching the seal as it is moved past theenlargement 22. The rounded portion 29 further permits the seal memberto be installed by an axial movement over the enlargement onto the tubeand, thus, replacement of the seal is effectively facilitated.

The assembly of the seal 20 on the tube end 12 may altematively beeffected by firstly moving the seal 20 over the tube end, andsubsequently forming the flared enlargement 22 as the flare may bereadily effected by conventional double flare tool means. Where the seal20 is formed of a relatively rigid material, such method of assemblingpermits the installation of the seal on the tube end with minimumstrain.

The seal 20 may be formed of any suitable seal material such as hightemperature plastic, rubber, etc. Where the fluids carried by the tube12 are corrosive, the seal may be of suitably formed anticorrosionmaterial, such as Teflon (tetrafluorethylene polymer).

As shown in FIG. 4, the outer diameter of the enlargement 22 ispreferably greater than the diameter of opening 18 in the flange 17 sothat should the tube 12 be forcibly pulled through the seal 20,notwithstanding the effectively positive support thereof as discussedabove, the flange provides a mechanical interlock effectively precludingwithdrawal of the tube end from the fitting.

As the tube end 12 is effectively supported in fitting 11 by theresilient seal 20, an improved vibration-resistant, flexible connectionof the tube end is obtained. Further, as the diameter of the opening 18is greater than the diameter of the tube 12, angular displacement of thetube end from the coaxial relationship shown in FIG. 3 is permitted. Thesupport of the tube 12 by the relatively long seal 20 provides a largearea of support for effectively minimizing tendency of crystallizationof the tube material which often results in fracture of the tubinginconventional flex fittings. Further, as the seal member is a simplesymmetrical cylindrical structure, it may be installed in eitherdirection and, thus, improper assembly on the tube end is precluded. Asthe seal member 20 backs on the flange 17, the need for backup rings andother similar conventional confining means as used in conventional flexfittings is eliminated. Further, as the enlargement 22 extends radiallyoutwardly from the normal inside diameter of the tube 12, the flowpassage through the connection end is unrestricted for improvedefficiency in the connection.

As shown in FIG. 5, the invention further comprehends the provision ofsuch a tube connection wherein the enlargement 122 may comprise aseparate element 132 secured to the tube end 130. Thus, the element 132,which may have an outer configuration generally similar to that of theconfiguration of enlargement 22, may be secured to the tube end as bybrazing, welding, adhesive means, or by constriction as at 131. Theenlargement 122 functions similarly as enlargement 22 in cooperatingwith the seal 20 for effectively positively supporting and retaining thetube end in the fitting against axial withdrawal from the space 19.

The foregoing disclosure of specific embodiments is illustrative of thebroad inventive concepts comprehended by the invention.

We claim:

I. In a tube connection including a fitting having an internal space forreceiving a tube end, an outer wall portion defining an opening throughwhich the tube end extends into said space, an inner wall portiondefining the inner end of said space, and a resilient annular seal insaid space inwardly adjacent said outer wall portion, said tube endextending in coaxially sealed association through said seal to axiallyinwardly thereof, the improvement comprising the provision on the tubeend of a formed radial enlargement defining the axially inner distalportion of said tube end coaxially abutting the axial inner end of saidseal whereby said seal effectively sealingly, resiliently supports saidtube end against axially outward withdrawal thereof from said space,said enlargement comprising a radially out-turned axially outer portionengaging said resilient seal in the normal made-up arrangement of thefitting, a radially inturned distal axially inner end portionconfronting said inner wall portion of the fitting whereby abutment ofsaid inner end portion with said inner wall portion limits axiallyinward movement of the tube end through said space, and a roundedradially outer portion permitting movement of the seal over saidenlargement both axially inwardly and outwardly to permit the seal to beinstalled on said tube end by movement thereof axially outwardly oversaid enlargement, and permit said enlargement to move axially outwardlythrough said seal into abutment with said outer wall as a result of anaxially outward urging of said tube end and to move subsequently axiallyinwardly to said normal made-up arrangement wherein said enlargement isdisposed axially inwardly of the seal said seal sealingly engaging saidfitting and said tube end in all axial positions of said tube endtherein.

2. The tube connection of claim 1 wherein the outside diameter of saidenlargement is larger than said wall portion opening to provide apositive mechanical interlock precluding withdrawal of said tube anddistal portion outwardly through said fitting wall portion opening.

3. The tube connection of claim 1 wherein said enlargement has an insidediameter substantially similar to that of the tube end.

4. The tube connection of claim 1 wherein the distal portion of saidenlargement is substantially flat perpendicular to the axis ofsaid tubeend.

5. The tube connection of claim 1 wherein the axially outward portion ofsaid enlargement tapers to a tubular connection with the tube end.

6. The tube connection of claim 1 wherein said enlargement comprises adeformation of the tube end corresponding to the first step of aconventional double type of tube flare.

7. The tube connection of claim 1 wherein said wall portion opening hasa diameter greater than the outside diameter of the tube end outwardlyof said enlargement to permit limited angular displacement of the tubeend extended therethrough.

8. The tube connection of claim 1 wherein said tube is retained againstaxial displacement from the tube connection solely by the resilient sealand the outer wall portion of the fitting.

9. The tube connection of claim I wherein the outer portion of saidenlargement is frustoconical extending axially outwardly.

10. The tube connection of claim 1 wherein said enlargement comprises acompressive deformation of the distal portion of the tube end.

ll. In a tube connection including a fitting having an internal spacefor receiving a tube end, an outer wall portion defining an openingthrough which the tube end extends into said space, an inner wallportion defining the inner end of said space, and a resilient annularseal in said space inwardly adjacent said outer wall portion, said tubeend extending in coaxially sealed association through said seal toaxially inwardly thereof, the improvement comprising the provision onthe tube end of a radially projecting element secured to the axiallyinner distal portion of said tube end coaxially abutting the axial innerend of said seal whereby said seal effectively sealingly, resilientlysupports said tube end against axially outward withdrawal thereof fromsaid space, said element comprising a radially and axially outer portionengaging said resilient seal in the normal made-up arrangement of thefitting, a radially and axially inner distal end portionconfronting'said inner wall portion of the fitting whereby abutment ofsaid inner end portion with said inner wall portion limits axiallyinward movement of the tube end through said space, and a roundedradially outer portion permitting movement of the seal over said elementboth axially inwardly and outwardly to permit the seal to be installedon said tube end by movement thereof axially outwardly over saidelement, and permit said element to move axially outwardly through saidseal into abutment with said outer wall as a result of an axiallyoutward urging of said tube end and to move subsequently axiallyinwardly to said normal made-up arrangement of the fitting wherein saidelement is disposed axially inwardly of the seal, said seal sealinglyengaging said fitting and said tube end in all axial positions of saidtube end therein.

12. The tube connection of claim 11 wherein said enlargement is securedto the tube end by brazing.

13. The tube connection of claim 11 wherein said enlargement is securedto the tube end by welding.

14. The tube connection of claim 11 wherein said enlargement is securedto the tube end by adhesive means.

15. The tube connection of claim 11 wherein the enlargement isconstrictively secured to the tube end.

1. In a tube connection including a fitting having an internal space forreceiving a tube end, an outer wall portion defining an opening throughwhich the tube end extends into said space, an inner wall portiondefining the inner end of said space, and a resilient annular seal insaid space inwardly adjacent said outer wall portion, said tube endextending in coaxially sealed association through said seal to axiallyinwardly thereof, the improvement comprising the provision on the tubeend of a formed radial enlargement defining the axially inner distalportion of said tube end coaxially abutting the axial inner end of saidseal whereby said seal effectively sealingly, resiliently supports saidtube end against axially outward withdrawal thereof from said space,said enlargement comprising a radially out-turned axially outer portionengaging said resilient seal in the normal made-up arrangement of thefitting, a radially inturned distal axially inner end portionconfronting said inner wall portion of the fitting whereby abutment ofsaid inner end portion with said inner wall portion limits axiallyinward movement of the tube end through said space, and a roundedradially outer portion permitting movement of the seal over saidenlargement both axially inwardly and outwardly to permit the seal to beinstalled on said tube end by movement thereof axially outwardly oversaid enlargement, and permit said enlargement to move axially outwardlythrough said seal into abutment with said outer wall as a result of anaxiAlly outward urging of said tube end and to move subsequently axiallyinwardly to said normal made-up arrangement wherein said enlargement isdisposed axially inwardly of the seal said seal sealingly engaging saidfitting and said tube end in all axial positions of said tube endtherein.
 2. The tube connection of claim 1 wherein the outside diameterof said enlargement is larger than said wall portion opening to providea positive mechanical interlock precluding withdrawal of said tube anddistal portion outwardly through said fitting wall portion opening. 3.The tube connection of claim 1 wherein said enlargement has an insidediameter substantially similar to that of the tube end.
 4. The tubeconnection of claim 1 wherein the distal portion of said enlargement issubstantially flat perpendicular to the axis of said tube end.
 5. Thetube connection of claim 1 wherein the axially outward portion of saidenlargement tapers to a tubular connection with the tube end.
 6. Thetube connection of claim 1 wherein said enlargement comprises adeformation of the tube end corresponding to the first step of aconventional double type of tube flare.
 7. The tube connection of claim1 wherein said wall portion opening has a diameter greater than theoutside diameter of the tube end outwardly of said enlargement to permitlimited angular displacement of the tube end extended therethrough. 8.The tube connection of claim 1 wherein said tube is retained againstaxial displacement from the tube connection solely by the resilient sealand the outer wall portion of the fitting.
 9. The tube connection ofclaim 1 wherein the outer portion of said enlargement is frustoconicalextending axially outwardly.
 10. The tube connection of claim 1 whereinsaid enlargement comprises a compressive deformation of the distalportion of the tube end.
 11. In a tube connection including a fittinghaving an internal space for receiving a tube end, an outer wall portiondefining an opening through which the tube end extends into said space,an inner wall portion defining the inner end of said space, and aresilient annular seal in said space inwardly adjacent said outer wallportion, said tube end extending in coaxially sealed association throughsaid seal to axially inwardly thereof, the improvement comprising theprovision on the tube end of a radially projecting element secured tothe axially inner distal portion of said tube end coaxially abutting theaxial inner end of said seal whereby said seal effectively sealingly,resiliently supports said tube end against axially outward withdrawalthereof from said space, said element comprising a radially and axiallyouter portion engaging said resilient seal in the normal made-uparrangement of the fitting, a radially and axially inner distal endportion confronting said inner wall portion of the fitting wherebyabutment of said inner end portion with said inner wall portion limitsaxially inward movement of the tube end through said space, and arounded radially outer portion permitting movement of the seal over saidelement both axially inwardly and outwardly to permit the seal to beinstalled on said tube end by movement thereof axially outwardly oversaid element, and permit said element to move axially outwardly throughsaid seal into abutment with said outer wall as a result of an axiallyoutward urging of said tube end and to move subsequently axiallyinwardly to said normal made-up arrangement of the fitting wherein saidelement is disposed axially inwardly of the seal, said seal sealinglyengaging said fitting and said tube end in all axial positions of saidtube end therein.
 12. The tube connection of claim 11 wherein saidenlargement is secured to the tube end by brazing.
 13. The tubeconnection of claim 11 wherein said enlargement is secured to the tubeend by welding.
 14. The tube connection of claim 11 wherein saidenlargement is secured to the tube end by adhesive means.
 15. The tubeconnection of claim 11 wherein the enlargement is constrictively securedto the tube end.